Source:http://linkedlifedata.com/resource/pubmed/id/10777518
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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
17
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pubmed:dateCreated |
2000-6-2
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pubmed:abstractText |
We report an EPR study of the iron-sulfur enzyme, anaerobic ribonucleotide reductase activase from Lactococcus lactis. The activase (nrdG gene) together with S-adenosyl-L-methionine (AdoMet) give rise to a glycyl radical in the NrdD component. A semi-reduced [4Fe-4S](+) cluster with an axially symmetric EPR signal was produced upon photochemical reduction of the activase. Air exposure of the reduced enzyme gave a [3Fe-4S](+) cluster. The Fe(3)S(4) cluster was convertible to the EPR-active [4Fe-4S](+) cluster by renewed treatment with reducing agents, demonstrating a reversible [3Fe-4S](+)- to-[4Fe-4S](+) cluster conversion without exogenous addition of iron or sulfide. Anaerobic reduction of the activase by a moderate concentration of dithionite also resulted in a semi-reduced [4Fe-4S](+) cluster. Prolonged reduction gave an EPR-silent fully reduced state, which was enzymatically inactive. Both reduced states gave the [3Fe-4S](+) EPR signal after air exposure. The iron-sulfur cluster interconversion was also studied in the presence of AdoMet. The EPR signal of semi-reduced activase-AdoMet had rhombic symmetry and was independent of which reductant was applied, whereas the EPR signal of the [3Fe-4S](+) cluster after air exposure was unchanged. The results indicate that an AdoMet-mediated [4Fe-4S](+) center is the native active species that induces the formation of a glycyl radical in the NrdD component.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Iron,
http://linkedlifedata.com/resource/pubmed/chemical/Iron-Sulfur Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Ribonucleotide Reductases,
http://linkedlifedata.com/resource/pubmed/chemical/S-Adenosylmethionine,
http://linkedlifedata.com/resource/pubmed/chemical/Sulfides
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
28
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pubmed:volume |
275
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
12367-73
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:10777518-Bacterial Proteins,
pubmed-meshheading:10777518-Electron Spin Resonance Spectroscopy,
pubmed-meshheading:10777518-Escherichia coli,
pubmed-meshheading:10777518-Iron,
pubmed-meshheading:10777518-Iron-Sulfur Proteins,
pubmed-meshheading:10777518-Lactococcus lactis,
pubmed-meshheading:10777518-Models, Chemical,
pubmed-meshheading:10777518-Oxidation-Reduction,
pubmed-meshheading:10777518-Ribonucleotide Reductases,
pubmed-meshheading:10777518-S-Adenosylmethionine,
pubmed-meshheading:10777518-Sulfides,
pubmed-meshheading:10777518-Time Factors
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pubmed:year |
2000
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pubmed:articleTitle |
Electron paramagnetic resonance evidence for a novel interconversion of [3Fe-4S](+) and [4Fe-4S](+) clusters with endogenous iron and sulfide in anaerobic ribonucleotide reductase activase in vitro.
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pubmed:affiliation |
Department of Biophysics, Arrhenius Laboratories, Stockholm University, S-106 91 Stockholm, Sweden.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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